I just fixed mine about six months ago. The above video gives you a feel for what is going on with the actual shifter and throttle. Remove the screws on the exposed black plate. The entire unit will then drop out of the side gunnel. At that point you will have what is displayed in the video above. You will have to remove the cables by pulling the pins. Then you can remove the shift/throttle assembly from the black plate and post that the lever attaches to. The lever comes off with the allen screw on the bottom of the lever. you can then see where the spring is and if it is broken or fatigued. I was able to go to the local mom/pop hardware store and find a replacement spring. I did have to cut the replacement spring down to the appropriate size (dremel cutting disc). Also, the small metal block/key gets rounded off over time. I was able to file it back to having better corners, which facilitates the locking effect. While you are working on the unit be sure and grease up all the moving parts on the actual shift/throttle assembly. The ease of function when I lubed everything was remarkable (don't lube the key/block or the slot that it fits in). I am reasonably mechanical but not a whiz, just pay attention to how it all comes apart. Good Luck and Enjoy !!!